Permitted Development Checker

Permitted development (PD) rights allow certain building works and changes of use without needing to apply for planning permission. They are set out in the Town and Country Planning (General Permitted Development) Order 2015 (as amended). PD rights apply to most houses but not to flats, listed buildings, or properties where an Article 4 direction applies.

For a single-storey rear extension the maximum projection from the rear wall of the original house is 4m (detached) or 3m (semi-detached and terraced) under GPDO Schedule 2 Part 1 Class A.1(f)(i). A single-storey rear extension must also not exceed 4m in overall height (Class A.1(f)(ii)) — so a 4.5m-high pitched-roof extension needs planning permission even if its depth is within limits. Under the Larger Home Extension prior-approval scheme, depths of up to 8m (detached) or 6m (semi/terrace) may be possible after a neighbour-consultation application, but the 4m height cap still applies — check with your council.

Outbuildings must: not cover more than 50% of the garden (curtilage), not be forward of the principal elevation, have a maximum height of 2.5m within 2m of a boundary, 4m with a dual pitch roof or 3m otherwise. They must be ancillary to the dwelling (not a separate dwelling) and cannot contain sleeping accommodation as the primary use.

Yes, conservation areas restrict some PD rights. Specifically: no cladding, no dormer windows on roof slopes facing the highway, no satellite dishes on front elevations, and side extensions are restricted. Outbuilding rules remain mostly the same. Always check with your local authority as some areas have additional restrictions via Article 4 directions.

Yes! Permitted development only relates to planning permission. You still need Building Regulations approval for structural work, electrical installations, drainage, and any habitable extensions. Building control must inspect and approve the work regardless of whether planning permission was needed.